1. Field of the Invention
The present invention relates to the recovery of oil from subterranean petroleum reservoirs, and more particularly, to an improved micellar solution flooding process for the recovery of petroleum from subterranean reservoirs.
2. The Prior Art
It is well recognized in the petroleum industry that substantial amounts of oil remain unrecovered in a petroleum reservoir at the completion of normal primary recovery operations. Thus, various secondary methods of recovering additional quantities of oil have been proposed such as water flooding, wherein water is injected into a petroleum reservoir through an injection well to drive additional oil toward one or more production wells.
More recently microemulsions or micellar solutions of surfactants and the like have been employed in enhanced oil recovery systems. For example, U.S. Pat. No. 4,252,192 to Nussbaum et al. relates to an enhanced oil recovery process which comprises injecting into a petroleum containing formation a micellar solution consisting of a hydrocarbon, water and a petroleum sulfonate and displacing said micellar solution through the petroleum containing formation to a production well.
U.S. Pat. No. 3,901,317 to Plummer et al. discloses an oil recovery process which comprises flooding oil bearing subterranean formations with a micellar dispersion containing two different petroleum sulfonates having an average equivalent weight within the range of about 390 to 450. The micellar dispersion is followed by a mobility buffer slug, such as, a high molecular weight polyacrylamide and a water drive to displace the aqueous sulfonate mixture toward a production well.
U.S. Pat. No. 3,933,20l to Kerfoot et al. relates to a method of preparing an overbased branched-chain alkylaromatic sulfonate. The alkylaromatic is described as suitable for use as a waterflood additive.
U.S. Pat. No. 4,013,125 to Plummer et al. relates to a process for flooding a subterranean formation with micellar dispersions containing petroleum sulfonates obtained by sulfonating whole or topped crude oil. The micellar dispersion contains water, a hydrocarbon, cosurfactant, electrolyte and petroleum sulfonate. Hydrocarbon is recovered from a subterranean formation by successively injecting the micellar dispersion, a mobility buffer and a water drive into said subterranean formation toward production means to recover hydrocarbons.
U.S. Pat. No. 3,913,674 to Krehbiel et al. relates to an anionic water flood additive and method of using the same to recover hydrocarbons from a petroliferous formation. The anionic water flood additive is an overbased sulfonate derived from catalytically or thermally cracked distillate refinery streams. The water flood additive is displaced through the formation to a petroleum production well.
U.S. Pat. No. 3,964,548 to Schroeder et al. discloses a process for recovering hydrocarbons from a subterranean formation using a micellar dispersion comprised of water, hydrocarbon, cosurfactant, electrolyte and petroleum sulfonate obtained by sulfonating whole or topped crude oil. The micellar dispersion is injected into a subterranean formation containing hydrocarbons and displaced toward oil production means.
As can readily be determined from the above, there is an ongoing effort to recover oil in enhanced oil recovery processes using micellar dispersions containing various sulfonates.
Accordingly, it is an object of the present invention to provide an improved process for recovering oil from a petroleum reservoir.
Another object of this invention is to provide an improved micellar dispersion fluid for use in an enhanced oil recovery process.
Still another object of the invention is to provide a micellar solution flooding process for recovering increased amounts of oil from subterranean petroleum reservoirs.
Other objects and advantages of the invention will be apparent from the following description.